Low water flow from old washing machine
I would not pour chemicals into the washing machine.
Sometimes the screens on the ports are in the form of removable rings although it may take some effort to get them out and they may be corroded enough to disintegrate in the process.
If you run the washing machine without screens in the water ports, you could have sediment enter the water passageways inside and cause other problems.
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.